Pump for discharging a predetermined quantity of fluid

ABSTRACT

A pump for discharging a predetermined quantity of fluid. The pump housing contains a reciprocating pumping member, which is preferably driven in a forward stroke by mechanical, hydraulic or pneumatic means under the control of a solenoid which, when energized, causes the pumping member to take the forward stroke, the length of which corresponds to the predetermined quantity of fluid to be delivered by the pump. The solenoid remains energized until the forward stroke is completed, at which time it is deenergized. The stroke length of the pumping member, and hence the amount of fluid delivered by the pump, is adjustable. The driving force for the return stroke of the pumping member is preferably accomplished by means of a spring which is loaded during the forward stroke, the force of the loaded spring being overcome by the solenoid as long as the solenoid is energized, or by hydraulic or pneumatic means controlled by a conventional distribution member under the influence of the solenoid.

United States Patent 11 1 Wolthers v May 14, 1974 PUMP FOR DISCI-IARGING A I 1 FOREIGN PATENTS OR APPLICATIONS PREDETERMINED QUANTITY OF FLUID 610,778 12/1960 Canada 417/403 [75] Inventor: Adolf Johan Wolthers, Kaarst,

Germany Primary Examiner-C. J. Husar 7 Assigneez papilla Establissemem, Vaduz, Attorney, Agent, or Firm-Hubbell, Cohen & Stiefel Liechtenstein 22 Filed: Nov; 11, 1971 [57] ABSTRACT [211 App] No 197 840 A pump for discharging a predetermined quantity of fluid. The pump housing contains a reciprocating I pumping member, which is preferably driven in a for- [30] Foreign Application Priority Data ward stroke by mechanical, hydraulic or pneumatic Nov, 23, 1970 Switzerland 17307/70 m ans nd h control of a l d which, when energized, causes the pumping member to take the [52] U.S. Cl 417/416, 92/98 D, 417/317, forward r k h ngth f w i h c rresp nds t the 417/345, 417/403 predetermined quantity of fluid to be delivered by the [51] Int. Cl. F04b 17/04 pump. The solenoid remains energized until the for- [58] Field of Search 92/98 D; 417/317, 326, ward r k is mp t hich im it is e- 417/402-404, 415, 416, 505, 345, 347 energized. The stroke length of the pumping member, l and hence the amount of fluid delivered by the pump, [56] References Cited is adjustable. The driving force for the return stroke of UNITED STATES PATENTS the pumping member is preferably accomplished by means of a spring which is loaded during the forward stroke, the force of the loaded spring being overcome 3:437:043 4,1969 sanders'ln 417/416 by the solenoid as long as the solenoid is energized, or 3,250,247 5/1966 Beaman 417/403 y hydraulic r Pneumatic means controlled y a 3,337,566 6 19 3 Temple 417 3 ventional distribution member under the influence of 3,326,135 6/1967 Smith 417/345 the solenoid. 3,044,405 7/1902 Bent 417/403 3,542,495 11/1970 Barthalon 417/416 13 Claims, 6 Drawing Figures I III F Joe I 42 24 w 51 1a 2a 19 2 :1 48 4g 7 26 2g )1 33 0 47 5 i I \l 55 $*'5 a g h l} 31 34 1' 52 21 r 54 5 1o 41 t l 23 13 22 11 a 9 sum 2 or 2 PATENTEDHAY 14 m4 3 w \s 4 z 1 PUMP FOR DISCHARGING A PREDETERMINED QUANTITY OF FLUID BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to pumps for discharging predetermined quantities of fluids.

2. Description of the Prior Art To-date there are no prior art pumps capable of discharging a predetermined quantity of a fluid which are of simple construction and can be manufactured economically. In addition, the dosage quantity discharged by prior art dosing pumps is not capable of being predictably varied or adjusted in a simple and efficient manner. The present invention overcomes these disadvantages of the prior art.

SUMMARY OF THE INVENTION A pump for discharging a predetermined quantity of fluid includes a pump housing and a reciprocating and is cooperatively associated with a rodlike member moving in unison therewith, the end of which rod-like member facing away from the pumping member being provided with a cylindrical portion having at its surface a single or multiplex screwthread carrying an internally threaded sleeve co-axial with but axially adjustable to the rod-like member and having a switching member for opening a limit switch, which switch is connected in the energizing circuit of the solenoid controlling the drive of the pumpingmember, during the travel of the sleeve in unison with the pumping member so as to interrupt the energizing or electric circuit and deenergize the solenoid. A second co-axial sleeve is slidably mounted over. the first mentioned co-axial sleeve but is preferably not rotatable thereon and is preferably journalled, with some axial play at most, in the pump housing. This second sleeve carries at its end protrud- -ing therefrom an adjusting knob for adjusting the axial position of the first mentioned co-axial sleeve with respect to the rod-like member of the pumping member, the resistance against rotation of the second co-axial sleeve being larger than the moment of rotation exerted thereon by the first mentioned co-axial sleeve upon the opening of the limit switch by the switching member.

According to the invention, the resistance against rotation of the second co-axial sleeve is preferably effected by at least one spring loaded locking means carried by the sleeve or by the pump housing and engaging a recess of a ring of identical recesses arranged in the pump housing or in the sleeve, respectively, the locking means on rotation of the sleeve successively engaging each subsequent recess with a snapping action.

In the preferred embodiment of the invention, in order that a quick interruption of the electric or energizing circuit of the solenoid is effected, in spite of the relative slow motion of the pumping member, so that sparking of the contact parts of the limit switch is prevented. the switch comprises a contact ring of electrically conductive material arranged around the second co-axial sleeve, the spring loaded end contacts of a pair of terminals conducted in an electrically insulated manner through the wall of the pump housing bearing against the periphery of the contact ring in the closed position of the limit switch. The contact ring can be moved axially by the switching member of the first coaxial sleeve after the resistance against the shifting of the ring has been surmounted by the switching member, the axial pressure exerted by the switching member being transmitted to the contact ring by spring action.

When it is desired to maintain the adjusting knob of a pump fully stationary, the contact ring is carried by an annular carrier of electrically insulating material,

the carrier being brought back by a spring into a position in which the limit switch is closed, the action of the spring being compensated by the switching member before it opens the switch. However, when movement of the adjusting knob on interruption of the electric or energizing circuit of the solenoid over a relatively small distance in the axial direction is permissible, the contact ring may be carried by the second co-axial sleeve made of electrically insulating material, this sleeve being axially movable in the pump housing with such a play, that it can be moved by the switching member into a position in which the limit switch is opened, and moved back to its starting position in which the switch is closed in response to the movement of the pumping member when it approaches the end of its return stroke.

In a simplified embodiment of the pump according to the invention, the end contacts of the switch take over the task of the spring loaded locking members effecting the resistance against rotation of the second co-axial sleeve. In such an embodiment of the pump, the contact ring is locked against rotation with respect to the second co-axial sleeve preferably by means of V- shaped axial grooves arranged in the periphery of the contact ring. Each of these grooves is preferably provided at the bottom thereof with a recess into which the contacts of the limit switch are snapped in its closed position, the carrier of the contact ring being provided with similar grooves in line with the grooves of the contact ring.

BRIEF DESCRIPTION OF DRAWING FIG. 1 is a longitudinal sectional view of the preferred embodiment of the pump of the present invention;

FIG. 2 is a cross sectional view taken along line II-II of FIG. 1;

FIG. 3 is a cross sectional view taken along line III- -III of FIG. 1;

FIG. 4 is a longitudinal sectional view of an alternative embodiment of the present invention;

FIG. 5 is a cross sectional view taken along line V V of FIG. 4; and

FIG. 6 is a diagrammatic illustration, partially in schematic, of the pump control network of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings in detail and especially to FIGS. 1-3 and 6 thereof, a preferred embodiment of the pump 108 of the present invention is shown. The

pump 108 is preferably driven by a hydraulic or pneumatic medium under pressure, the inlet and discharge of this medium and of the fluid to be dosed or discharged being, preferably, controlled by distribution slide valve or by a distribution cock (not shown), the movement of which is preferably controlled by a solenoid 102 (FIG. 6). The circuit (FIG. 6) comprising the pump 108 and the solenoid 102 which controls the pump distribution member located centrally inside the pump housing is arranged in such a manner that the electric or energizing circuit of the solenoid 102 is closed on receiving an impulse (for instance one effected by the manual actuation of a push button 104 or by the momentary closing of a switch in the circuit by a cam) and is maintained in the closed condition by an electromagnetic switch in the circuit of the solenoid or by a spring loaded switch 109 controlled by the distribution member, the electromagnetic switch or the spring loaded switch 109 being connected in parallel with the push button 104 or the switch for imparting an electric impulse to the solenoid. A switch which opens when a stop actuated by the pumping member of the pump abuts against the switch member of this latter switch is also preferably connected in the electric or energizing circuit of the solenoid. Therefore, on excitation of the solenoid it shifts the distribution member (slide valve or cock) into its operative position, which distrubution member on interruption of the excitation of the solenoid is moved back to its starting position by spring action. Consequently, on receiving an electric impulse the solenoid controls distrubuting member distrubutingmember of the pump in such a manner, that the pumping member of the pump executes one forward stroke and one return stroke.

Now describing the embodiment shown in FIGS. 1-3 in greater detail. The pump preferably includes a cylindrical housing portion 1, in whch a pumping member constituted by a piston 2 is movable. Piston 2 is pro vided with a sealing member generally indicated by reference numeral 3. One end of the cylindrical housing portion 1, which forms a pumping chamber, is closed by a bottom wall 4 and the other end by a partition wall 5.

The pumping chamber 6 is divided by piston 2 into two sections, one section or chamber is defined by the partition wall and piston 2, and the other section or chamber is defined by the piston 2 and the bottom wall 4. The volume of the chamber defined by piston 2 and bottom wall 4, with piston 2 in the position shown in FIG. 1, is essentially zero for all practical purposes. A conduit or passageway 7 is located in the partition wall 5 and communicates between a connecting nipple 8 and the pump chamber defined by piston 2 and partition wall 5. Another conduit or passageway 9 is located in bottom wall 4 and communicates between a connecting nipple 10 and the pump chamber defined by piston 2 and bottom wall 4. A tube (not shown) for the fluid to be dosed can be connected to each of the connecting nipples 8 and 10, the other ends of the tubes being connected to the distributing member (slide valve or cock, which is a conventional distribution means and is omitted for purposes of clarity) controlled by the solenoid. When the solenoid is not energized or excited the distribution member assumes a position in which the conduit 9 is in open communication with a discharge conduit (not shown) for the fluid to be dosed and in which position the conduit 7 is in open communication with an inlet conduit (not shown) for this fluid. When the solenoid is excited or energized, the distribution member is shifted into a position in which the conduit 9 is in open communication with the inlet conduuit for the fluid to be dosed and in which position the conduit 7 is in open communication with the discharge conduit therefor.

A pumping member in the form of a diaphragm 14 of flexible material, such as rubber, is preferably clamped along its periphery between a flange 11 of the housing portion 1 and a flange 12 of a second housing portion 13 of electrically insulating material, such as plastic. The diaphragm 14 is preferably clamped tightly at its center between a disc 15 carried by a central rod 17 of the pump piston 2 and a cylindrical co-axial portion 18 of rod 17. Rod 17 of piston 2 is preferably slidably sealed in a central bore of the partition wall 5. The diaphragm 14 is kept clamped by the cylindrical portion 18 by means of a cup-shaped spring bracket 19 of a compression spring 20 arranged between this bracket and an inner shoulder 21 of housing portion 13.

The interior space of housing portion 13 is divided by the diaphragm 14 into a chamber 22 limited by the partition wall 5 and into a chamber 23 present at the other side of the diaphragm 14 which chamber 23 is in communication with the ambient atmosphere by an opening 101 in the wall of housing portion 13.

Chamber 22 is preferably in open communication with a conduit or passageway 24 located in the partition wall 5 and ending in a connecting nipple 25 to which a tube (not shown) for the hydraulic or pneumatic medium under pressure for driving the pump is preferably connected.

Upon the excitation or energizing of the solenoid controlling the distribution member, the tube connected to the nipple 25 is preferably put in open communication with an inlet conduit for the medium under pressure. Upon interruption of the excitation of the solenoid, the tube connected to nipple 25 is preferably put in open communication with a discharge conduit for the exhausted medium. During this operation piston 2 carries out one forward stroke, against the action of spring 20, under the influence of the medium under pressure and, subsequently, a return stroke under the action of spring 20.

During the stroke of the piston 2 in the direction of the partition wall 5, which for purposes of explanation shall be termed the forward stroke, the fluid present in the section of the chamber 6 between piston 2 and partition wall 5 is preferably discharged through conduit 7 and the fluid to be dosed is sucked into the section of the chamber 6 between piston 2 and bottom wall 4 through conduit 9. During the return stroke of piston 2, the section of the chamber 6 between piston 2 and bottom wall 4 is emptied through conduit 9 and the fluid to be dosed is sucked into the section of the chamber 6 between piston 2 and partition wall 5 through conduit 7. As previously mentioned, the relative functions of conduits 7 and 9 as, alternately, inlet and outlet passageways for intake of the fluid to be closed and, respectively, discharge of the fluid from the appropriate section of the chamber 6 is controlled by the positioning of the distribution member which is, in turn, controlled by the solenoid.

The surface of the cylindrical portion 18 of rod 17 is provided with two diametrically opposed helical grooves 26 and 27 having a pitch at least equal to the maximum stroke length of piston .2. A first co-axial sleeve 28 is rotatable around cylindrical portion 18 and is provided at its inner side with two cams 29 which are diametrically opposed to each other, each being in engagement with one of the helical grooves 26 and 27. Thus, when sleeve 28 is rotated with respect to the cylindrical portion 18 it is displaced in an axial direction in relation to that portion 18.

The first co-axial sleeve 28 fits slidably in an axial direction in a second sleeve 30 which is also co-axial with the central rod 17 of the pumping member 2 but which second sleeve is preferably not rotatable with respect to sleeve 28. The second sleeve 30 is rotatably journalled in housing portion 13 and is preferably locked against movement in the axial direction. The first coaxial sleeve 28 is preferably locked against rotation with respect to the second co-axial sleeve 30 by external axial ridges 31 slidably engaging corresponding axial grooves 32 in the inner wall of the second co-axial sleeve 30. The end 33 of sleeve 30 protruding from housing portion 13 preferably carries an adjusting knob 34 rigidly secured to the sleeve 30. Therefore, the axial position of sleeve 28 with respect to piston 2 and sleeve 30 can be adjusted as desired by rotation of knob 34,

and, thus, as will be explained in greater detail hereinafter, the capacity or quantity of fluid dischargeable by the pump during one working cycle can be predictably varied or adjusted to any desired amount, merely by changing the forward stroke of the piston 2. Sleeve 30 is provided with two flanges 35 and 36 between which extend ribs 37 (FIG. 2) opposing each other diametri cally. Each of these ribs has a bore in which a locking member 39 constituted by'a ball can move under the influence of a compression spring 38. A cylindrical por tion 40 of the housing portion 13 is provided with internal axial grooves 41 (by way of example twelve such grooves 41' are shown) into which the balls 39 snap successively on rotation of sleeve 30. g

The cylindrical portion 40 is preferably co-axial with another cylindrical portion 42 of the housing portion 13 of electrically insulating material, and preferably extends into spring 20 for a portion of its length. The annular wall portion-43 (FIG. 2) of the housing portion 13 connecting the cylindrical portions 40 and 42 and constituting the shoulder 21 is preferably provided with two ribs 44 arranged diametrically opposite to each other, each having a radial bore which preferably contains a terminal 45 of the limit switch contained in the electrical or energizing circuit of the solenoid which controls the distribution member of the pump. .Each terminal 45 has a central bore in which an end contact 47 constituted by a ball can slide under the action of a compression spring 46. In the closed position of the limit switch, the balls 47 are pushed against the periphery of a contact ring 48 of electrically conductive material which constitutes a switching member, which ring is carried by a bushing 49 of electrically insulating material. Bushing 49 is preferably mounted slidably in the axial direction on a bushing 50 which is also similarly preferably mounted slidably in the axial direction between the second co-axial sleeve 30 and the bushing 49 and is guided by sleeve 30. At each of its ends bushing 50 is provided with a flange 51 and 52, respectively. A compression spring 53 preferably bears on flange 52 of bushing 50 and on flange 35 of the second coaxial sleeve 30 and preferably pushes bushing 50 into the position shown in FIGS. 1 and 3. In this position of bush- 6 ing 50, its flange 52 rests against bushing 49 carryin contact ring 48. The limit switch, which is constituted by the parts 45, 47 and 48, is closed when bushing 49 occupies the position shown in the drawing (FIG. 1). A ring 53 is preferably located in an annular groove in the inner wall of the cylindrical housing portion 40 and constitutes a stop for bushing 49 so that spring 53 in conjunction with bushing 50 can push the bushing 49 carrying the contact ring 48 into a position in which the end contacts 47 rest against a cylindrical portion of the periphery of the contact ring 48. This cylindrical portion of the periphery of the contact ring 48 preferably has a smaller diameter than the outer wall of bushing 49 which is guided by the inner wall of the cylindrical housing portion 40, the cylindrical portion of the contact ring 48 preferably merging by means of a conical surface with the outer surface of bushing 49.

Preferably, between flange 51 of bushing 50 and bushing 49 a compression spring 54 is mounted. The action of this spring 54 will be explained in greater de' tail with reference to the operation of the pump.

The cylindrical housing portion 40 is preferably provided with axial external ribs 56, four being shown by way of example, each rib preferably having a bore 57 having screwthread therein for a fastening bolt for securing the pump to a support, for instance to a fixed wall provided with an opening corresponding to the end 33 of sleeve 30.

OPERATION OF EMBODIMENT OF FIGS. 1-3

When the electric or energizing circuit of the solenoid which controls the distributing member of the pump is closed, the distribution member is moved by the solenoid into 'a position in which conduit 24 is in open communication with the inlet conduit of the distribution member for the medium under pressure, con

duit 9 is in open communication with the inlet conduit of the distribution member for the fluid to be dosed, and conduit 7 is in open communication with the discharge conduit of the distribution member for this fluid. In this position of the distribution member, diaphragm 14 is moved (to the left as shown in the example of FIG. 1) against the action of spring 20 by the medium under pressure which fills chamber 22, so that pumping member or piston 2 carries out a stroke in the direction of partion wall 5. During this movement of the pumping member, the fluid to be dosed present in chamber 6 between piston 2 and partition wall 5 is discharged in proportion with the stroke length covered by the pumping member 2 and an equal quantity of the fluid to be dosed is sucked into the section of the chamber 6 formed between pumping member 2 and bottom wall 4.

The cylindrical portion 18 of rod 17 is provided with a switching cam constituted by a flange 55, flange 51 of bushing 50" being in the path of this switching cam 55. When switching cam 55-abuts against flange 51 of bushing 50, this bushing moves in unison with the pumping member 2, during which movement springs 53 and 54 are compressed and flange 52 of bushing 50 no longer contacts the end of bushing 49.

When the tension of spring 54 reaches such a value that the conical surface of ring 48 urges the end contacts back in their bores or when the windings of spring 54 rest against each other, bushing 49 slowly moves in an axial direction (to the left in the example of FIG. 1) until the bevelled end of the cylindrical surface of ring 48 has reached balls 47. At this moment the resistance of bushing 49 and, thus, of ring 48, against movement in the axial direction vanishes and bushing 49 together with the contact ring is moved by the spring 54 with a snapping action into a position in which the windings of spring 53 rest against each other and in which the end contacts 47 rest against the surface of bushing 49 of electrically insulating material. As a result of this the electric or energizing circuit of the solenoid which controls the distribution member is interrupted or opened so that the distribution member returns under spring action to its starting position in which the conduit 24 is again connected with the discharge conduit of the distribution member for the medium under pressure. In the latter position of the distribution members, conduit 9 is again in open communication with the discharge conduit of the distribution member for the fluid to be dosed, and conduit 7 is again in communication with the inlet conduit of the distribution member for the fluid to be dosed. Thereupon pumping member 2 under the action of spring 20, which was loaded during the forward stroke, carries out a return stroke during which the quantity of fluid to be dosed present in the section of the chamber 6 between the pumping member 2 and bottom wall 4 is discharged and an equal quantity of this fluid is sucked into the section of the chamber 6 between partition wall 5 and pumping member or piston 2.

When the limit switch 45-47-48 of the pump is closed under the action of spring 53 during the return stroke of the pumping member, the electric or energizing circuit of the solenoid remains interrupted because the electromagnetic switch or the switch (109 in FIG. 6) operated by the solenoid distribution member controlling the pump opens when this circuit is interrupted.

Since the stroke length of the pumping member 2 is determined by the position of the switching cam 55 acting on flange 51 of bushing 50, the quantity of fluid to be dosed by the pump can be adjusted by rotation of knob 34. Because the pitch of the helical grooves 26 and 27 substantially corresponds to the maximum stroke length of the pumping member 2, and desired quantity of the fluid to be dosed can be adjusted over the full range of the pump by rotating knob 34 over less or at the most over 360. If desired, a scale division can be utilized in conjunction with the knob 34 on which the adjusted quantity of fluid to be discharged by the pump can be read directly by calibrating the degree of rotation to the stroke length and, hence, to the quantity of fluid to be closed.

As mentioned, spring 54 is compressed when the switching member 55 abuts against flange 51 of bushing 50. Owing to this, an axial force is exerted on sleeve 28. Because the earns 29 of sleeve 28 engage the helical grooves 26, 27 of portion 18, sleeve 28 has the inclination to rotate (counter clockwise in the example of FIGS. 2 and 3). Such rotation is prevented by the second co-axial sleeve 30 with respect to which sleeve 28 is locked against rotation as mentioned. In turn, sleeve 30 is prevented from rotation by the locking means 39 engaging the grooves 41. Rotation of the cylindrical portion 18 in the clockwise direction (in the example of FIGS. 2 and 3) is also prevented because diaphragm 14 is clamped between the flanges I1 and 12.

For purposes of clarity, in FIGS. 1 and 2 the nuts of the inner wall of the cylindrical housing portion 40 are shown in a different position in FIG. 3 from that shown in FIGS. 1 and 2. Similarly, the grooves 32 in the inner wall of the second co-axial sleeve 30 are shown in a different position in FIGS. 2 and 3, from that shown in FIG. 1 for purposes of clarity.

The distribution member may be connected with the connecting nipples 8 and 25 also in such a manner, that in its position of rest the conduit 8 is connected with the inlet conduit for the medium under pressure and conduit 24 is connected with the discharge conduit for the medium under pressure. Upon excitation or energizing of the solenoid this situation is reversed. In such an instance, spring 20 may be eliminated because the return movement of the diaphragm 14 would be effected by the medium under pressure. Since the fluid to be dosed in such an instance is sucked in and discharged, respectively, only by conduit 9, the pump discharges only approximately half the quantity of fluid at each forward and return stroke of piston 2.

ALTERNATIVE EMBODIMENT Referring now to FIGS. 4 and 5, an alternative embodiment of the pump of the present invention is shown. The embodiment of the pump shown in FIGS. 4 and 5 is arranged insuch a manner, that it is preferably driven directly by a solenoid, the limit switch of the pump being connected in the energizing circuit for this solenoid in the same manner as shown in FIG. 6. In this alternative embodiment, the excitation of the solenoid is preferably started by a momentary electric impulse, for example by means of a push button (see FIG. 6) with which an electromagnetic switch or a switch (similar to switch 109 in FIG. 6) influenced by a spring and actuated by the solenoid is connected in parallel in the electric or energizing circuit of the solenoid.

The housing of the pump shown in FIGS. 4 and 5 preferably includes two cylinders 58 and 59 of electrically insulating material, such as plastic, in one piece, a bottom 60, and diaphragm 61 of rubber, or another material having a sufflcient flexibility, being clamped along its periphery between bottom 60 and flange 62 of the cylindrical housing portion 58. Bottom 60 is preferably provided with a connecting nipple 63 for an inlet conduit for the fluid to be dosed and with a connecting nipple 64 for a discharge conduit for this fluid. Nipple 63 is provided with an inlet valve and nipple 64 with an outlet valve for this fluid.

A disc 66 is preferably vulcanized into the center of diaphragm 61. A central piston rod 67 protruding from the pump housing 58, 59 is preferably secured to disc 66, such as by welding. Rod 67 preferably carries a cylindrical portion 68 which is co-axial to rod 67 and rigidly secured to it. The cylindrical portion 68 is preferably provided with two helical grooves 69 and 70 which are diametrically opposite to each other and into which engage two diametrically opposed earns 71, 72, respectively, of the inner wall of a first co-axial sleeve 73 rotatably mounted on cylindrical portion 68.

A cup-shaped spring bracket 74 which accommodates the end of a compression spring 75, the other end of which bears against a shoulder 77 formed by the annular wall 76 (FIG. 5), is preferably located between diaphragm 61 and the cylindrical portion 68.

The first co-axial sleeve 73 is preferably slidable in an axial direction in a second sleeve 78 of electrically insulating material and is co-axial with rod 67 and rotatablymounted in an extension 79 of the cylindrical housing portion 59 and extends within spring into the cylindrical housing'portion 58. Sleeve 73 is preferably provided with a plurality of external axial ribs 80 slidably engaging corresponding axial grooves 81 in the inner wall of sleeve 78, so that the sleeves 73 and 78 preferably cannot rotate with respect to each other. Sleeve 78 further is preferably rotatably mounted in a bore of a bolt 82 screwed into the cylindrical housing portion 59,

the bolt 82 being co-axial with rod 67, and by means of which bolt the pump can be secured in an opening of a support. The end of sleeve 78 protruding from bolt 82 constitutes an adjusting knob 83 by means of which the position of sleeve 73 can be adjusted in an axial direction and which also constitutes a bearingfor rod 67.

The limit switch in the electric or energizing circuit of the solenoid driving the pump is preferably constituted partially by two terminals 85 secured in the bores of two diametrically opposed ribs 84 of the annular wall 76. Each terminal 85 is provided with a longitudinal bore for accommodating an end contact 87 constituted by a ball loaded by a spring 86, which ball is slidably mounted in the bore. When the pump is at rest, balls 87 are each pushed into a round recess 88 by springs 86. A ring of such recesses 88 is preferably arranged in a radial plane me contact ring 89 of electrically conductive material and carried by sleeve 78. Contact ring 89 is rigidly secured to sleeve 78, each of the recesses 88 preferably being located at the bottom of an axial V- shaped groove 90 at the periphery of ring 89. Corresponding V-shaped grooves 92 arepreferably located, in line with the grooves 90, in the outer wall of the cylindrical portion 91 of sleeve 78 and guided by the extension 79 of the housing.

A nut 93 locked by a locknut 94 is preferably screwed on to the end of the piston rod 67 protruding from the bore of the securing bolt 82. Nut 93 is preferably provided with a radial bore 95 into which is secured one end of a schematically shown spring 96, the other end of which is connected to the armature of the solenoid (not shown) driving the pump.

The end of the first co-axial sleeve facing away from diaphragm 61 is preferably provided with an end wall 97 constituting a switching cam and having a central opening through which piston rod 67 extends. A compression spring 98 is preferably arranged around the portion of rod 67 extending between the end wall 97 and the adjusting knob 83.

OPERATION OF ALTERNATIVE EMBODIMENT (FIGS. 4-5) When the solenoid, the armature of which is connected to spring 96, it excited or energized, such as by a transitory actuation of a push button connected to its electric or energizing circuit, this circuit being kept closed by an electromagnetic switch or by a switch actuated by the solenoid driving the pump which switches are connected in parallel with the switch for initiating the energizing of the solenoid, the pumping member (diaphragm 61 in this embodiment) carries out a forward stroke (away from bottom 60 in the example of FIGS. 4 and During this stroke of the pumping member, fluid to be closed is sucked into the pump chamber and spring 75 is tensioned. When the disphragm 61 has covered the forward stroke, the length of which is determined by the position of sleeve 68 with respect to sleeve 78, spring 98 present between the switching cam 97 and the adjusting knob 83 is compressed.

When spring 98 has reached a tension which corresponds to the force required to move sleeve 78 in an axial direction against the action of springs 86, the balls 87 leave the round recesses 88 and sleeve 78 in brought with a snapping action into a position in which contact ring 89 rests against a shoulder 99 arranged in the housing portion 59. In this position of sleeve 78, the balls 87 constituting. the end contacts of the switch rest against the surface of portion 91 of sleeve 78. Because sleeve 78 consists of electrically insulating material, the electric or energizing circuit of the solenoid is interrupted by this snapping movement of sleeve 78. Diaphragm 61 then carries out its return stroke under the influence or drive of compression spring which had been loaded or tensioned during the forward stroke of the diaphragm 61. During this return stroke of the diaphragm 61, the fluid sucked into the pumping chamber is discharged through the outlet valve. Because the stroke length of the diaphragm 61 is determined by the axial position of sleeve 68 with respect to sleeve 78, it is clear that the quantity of fluid discharged by the pump can be adjusted by rotation of knob 83. Also, with this embodiment of the pump, each desired quantity of fluid to be discharged by the pump can be adjusted over its full range by rotation of knob 83 over at the most 360, because the pitch of the helical grooves 69 and 70 substantially corresponds with the maximum stroke length of the pumping member 61. Thus, as mentioned with respect to the embodiment shown in FIGS. 1-3, the degree of rotation of the knob may readily be calibrated to the stroke length and, hence, to the quantity of fluid discharged by the pump.

Because each of the spring loaded end contacts 87 engages the subsequent axial groove 90 of sleeve 78 each time knob 83 is rotated, and because every groove 92 of the portion 91 of sleeve 78 is in line with the corresponding groove 90, sleeve 78 is locked against rotation during the opening procedure of limit switch -8- 6-87-89, so that the position of this sleeve as adjusted is maintained.

When diaphragm 61 approaches the end of its return stroke, nut 94 abuts against the adjusting knob 83 and moves this back to the starting position illustrated in FIG. 4. Preferably, a ring 100 arranged in an annular groove in the inner wall of the extension 79 of the housing portion 59 determines the end position of sleeve 78 during this movement back to its starting position.

It will be clear that with the embodiment of the pump shown in FIGS. 4 and 5, the end contacts 87 take over the task of the locking means 39 of the embodiment shown in FIGS. 1-3. If, in this latter embodiment, the bushings 49 and 50 as well as spring 53 are eliminated and contact ring 49 is carried directly by sleeve 30, and if these latter parts are provided with grooves corresponding with the grooves and 92 of the contact'ring 89 and of the sleeve 7 8, respectively, and if the contact ring 48 has the same shape as contact ring 89, then the locking means 39 can also be eliminated. It has to be realized however, that with such a modification, the adjusting knob 34 moves over a short distance in the axial direction when the limit switch 4546-4748, is opened.

Since the pump of the present invention can be connected in such a manner in the energizing circuit of a solenoid that on receiving an electric impulse by the solenoid the pump carries out only a single forward stroke and a return stroke and discharges during this 1 1 operation a previously adjusted quantity of fluid, it is very suited for devices in which the switch for putting the pump into operation is actuated by a manually actuated push button or by a cam of a programming disc of the device.

As used throughout the specification and claims, the term fluid is meant to include gasses as well as liquids, including viscous mediums.

It is to be understood that the above described embodiments of the invention are merely illustrative of the principles thereof and that numerous modifications and embodiments of the invention may be derived within the spirit and scope thereof.

What is claimed is:

1. A pump for discharging a predetermined dosage quantity of a fluid comprising a pump housing, said housing including a pump chamber, said chamber having an inlet and outlet passageway in communication with the exterior of said pump chamber, said inlet passageway being in communication with a source of said fluid, said outlet passageway being capable of discharging said dosage therefrom, distribution means for controlling said fluid inlet and outlet passageways for controlling the discharge of said fluid, a reciprocatably movable pumping member within said chamber, means for reciprocatably driving said pumping member, said driving means including solenoid means for controlling said reciprocation in accordance with a state of said solenoid means, said solenoid means having an excitation state and an excitation interruption state andcontrolling the operation of said distribution means in accordance with said solenoid means state, said solenoid means enabling said pumping member to be driven from a rest position to a forward stroke position when said solenoid means is in said excitation state and to be returned via a return stroke to said rest position to complete said reciprocation when said solenoid means is in said excitation interruption state, said pumping member including means associated therewith for maintaining said solenoid means in said excitation state at least until said pumping member has been driven to said forward stroke position, said forward stroke position being a predetermined distance from said rest position whereby said pumping member traverses a volume in said chamber corresponding to said predetermined dosage quantity of fluid, said solenoid means including a limit switch for switching said solenoid means from said excitation state to said excitation interruption state when said limit switch is actuated from a closed position to an open position, said limit switch being actuated to said open position when said pumping member reaches said forward stroke position; said pumping member further including a rod-like member movable in unison therewith, said rod-like member including a cylindrical portion having an internally threaded first sleeve co-axial with and axially adjustable with respect to said rod like member and having a switching means thereon for actuating said limit switch to an open position when said first sleeve has travelled in unison with said pumping member to said forward stroke position of said pumping member, and a second co-axial sleeve slidably mounted over said first sleeve so as to be substantially non-rotatable thereon, said second sleeve including an adjusting knob thereon for adjusting the axial position of siad first sleeve with respect to said rod-like member, said second sleeve having a resistance against rotation greater than any amount of rotation exerted by said first sleeve upon said actuation of said limit switch to said open position.

2. A pump in accordance with claim 1 wherein said pump further includes means for varying the forward stroke position distance so as to vary the predetermined quantity of fluid to be discharged.

3. A pump in accordance with claim 1 wherein said drive means includes a source of pressurized medium, said housing further including an inlet and outlet passageway in communication with said pressurized medium source and said pumping member for reciprocatably driving said pumping member, said distribution means controlling said pressure medium passageway and said fluid passageway for controlling the discharge of said fluid.

4. A pump in accordance with claim 1 wherein said drive means includes resilient means for applying a force to said pumping member to bias said pumping member toward said rest position, said drive means including means for overcoming said bias force and enabling said pumping member to be driven to said forward stroke position when said solenoid means is in said excitation state, said bias force driving said pumping member back to said rest position when said solenoid means is in said excitation interruption state.

5. A pump in accordance with claim 4 wherein said drive means comprises hydraulic drive means for overcoming said bias force and driving said pumping member to said forward stroke position.

6. A pump in accordance with claim 4 wherein said drive means comprises pneumatic drive means for overcoming said bias force and driving said pumping member to said forward stroke position.

7. A pump as in claim 1 wherein said second sleeve includes at least one spring loaded locking means engageable in a recess of a ring of identical recesses arranged in said pump housing, said locking means on rotation of said second sleeve successively engaging each subsequent recess with a snapping action, whereby said second sleeve resistance against rotation is effectuated.

8. A pump as in claim 1 wherein said pump housing includes at least one spring loaded locking means engageable in a recess of a ring of identical recesses arrangedin said second sleeve, said locking means on rotation of said second sleeve successively engaging each subsequent recess with a snapping action, whereby said second sleeve resistance against rotation is effectuated.

9. A pump as in claim 1 wherein said limit switch comprises a contact ring of electrically conductive material arranged around the second co-axial sleeve, against the periphery of which contact ring in the closed position of the limit switch bear the springloaded end contacts of a pair of terminals conducted in an electrically insulated manner through a wall of the pump housing, which contact ring can be moved axially by the switching member of the first co-axial sleeve after a predetermined amount of resistance against shifting of said ring has been surmounted by said switching member, the axial pressure exerted by the swtiching member being transmitted to the contact ring by spring action.

10. A pump as in claim 9 wherein the contact ring is carried by an annular carrier of electrically insulating material, which carrier is brought back by a spring into a position in which the limit switch is closed, the action of which spring is compensated by the switching member before said switching member opens said switch.

11. A pump as'in claim 9 in which the contact ring is carried by the second co-axialsleeve made of electrically insulating material, said second sleeve being axially movable in the pump housing with such a play, that it can be moved by the switching member into a position in which the limit switch is open, and is moved back to its starting position in which said switch is closed in response to the movement of the pumping member when the pumping member approaches the end of its return stroke.

12. A pump as in claim 11 in which the contact ring is locked against rotation with respect to the second coaxial sleeve by means of V-shaped axial grooves arlength of the pumping member. 

1. A pump for discharging a predetermined dosage quantity of a fluid comprising a pump housing, said housing including a pump chamber, said chamber having an inlet and outlet passageway in communication with the exterior of said pump chamber, said inlet passageway being in communication with a source of said fluid, said outlet passageway being capable of discharging said dosage therefrom, distribution means for controlling said fluid inlet and outlet passageways for controlling the discharge of said fluid, a reciprocatably movable pumping member within said chamber, means for reciprocatably driving said pumping member, said driving means including solenoid means for controlling said reciprocation in accordance with a state of said solenoid means, said solenoid means having an excitation state and an excitation interruption state and controlling the operation of said distribution means in accordance with said solenoid means state, said solenoid means enabling said pumping member to be driven from a rest position to a forward stroke position when said solenoid means is in said excitation state and to be returned via a return stroke to said rest position to complete said reciprocation when said solenoid means is in said excitation interruption state, said pumping member including means associated therewith for maintaining said solenoid means in said excitation state at least until said pumping member has been driven to said forward stroke position, said forward stroke position being a predetermined distance from said rest position whereby said pumping member traverses a volume in said chamber corresponding to said predetermined dosage quantity of fluid, said solenoid means including a limit switch for switching said solenoid means from said excitation state to said excitation interruption state when said limit switch is actuated from a closed position to an open position, said limit switch being actuated to said open position when said pumping member reaches said forward stroke position; said pumping member further including a rod-like member movable in unison therewith, said rod-like member including a cylindrical portion having an internally threaded first sleeve co-axial with and axially adjustable with respect to said rod like member and having a switching means thereon for actuating said limit switch to an open position when said first sleeve has travelled in unison with said pumping member to said forward stroke position of said pumping member, and a second co-axial sleeve slidably mounted over said first sleeve so as to be substantially non-rotatable thereon, said second sleeve including an adjusting knob thereon for adjusting the axial position of siad first sleeve with respect to said rod-like member, said second sleeve having a resistance against rotation greater than any amount of rotation exerted by said first sleeve upon said actuation of said limit switch to said open position.
 2. A pump in accordance with claim 1 wherein said pump further includes means for varying the forward stroke position distance so as to vary the predetermined quantity of fluid to be discharged.
 3. A pump in accordance with claim 1 wherein said drive means includes a source of pressurized medium, said housing further including an inlet and outlet passageway in communication with said pressurized medium source and said pumping member for reciprocatably driving said pumping member, said distribution means controlling said pressure medium passageway and said fluid passageway for controlling the discharge of said fluid.
 4. A pump in accordance with claim 1 wherein said drive means includes resilient means for applying a force to said pumping member to bias said pumping member toward said rest position, said drive means including means for overcoming said bias force and enabling said pumping member to be driven to said forward stroke position when said solenoid means is in said excitation state, said bias force driving said pumping member back to said rest position when said solenoid means is in said excitation interruption state.
 5. A pump in accordance with claim 4 wherein said drive means comprises hydraulic drive means for overcoming said bias force and driving said pumping member to said forward stroke position.
 6. A pump in accordance with claim 4 wherein said drive means comprises pneumatic drive means for overcoming said bias force and driving said pumping member to said forward stroke position.
 7. A pump as in claim 1 wherein said second sleeve includes at least one spring loaded locking means engageable in a recess of a ring of identical recesses arranged in said pump housing, said locking means on rotation of said second sleeve successively engaging each subsequent recess with a snapping action, whereby said second sleeve resistance against rotation is effectuated.
 8. A pump as in claim 1 wherein said pump housing includes at least one spring loaded locking means engageable in a recess of a ring of identical recesses arranged in said second sleeve, said locking means on rotation of said second sleeve successively engaging each subsequent recess with a snapping action, whereby said second sleeve resistance against rotation is effectuated.
 9. A pump as in claim 1 wherein said limit switch comprises a contact ring of electrically conductive material arranged around the second co-axial sleeve, against the periphery of which contact ring in the closed position of the limit switch bear the springloaded end contacts of a pair of terminals conducted in an electrically insulated manner through a wall of the pump housing, which contact ring can be moved axially by the switching member of the first co-axial sleeve after a predetermined amount of resistance against shifting of said ring has been surmounted by said switching member, the axial pressure exerted by the swtiching member being transmitted to the contact ring by spring action.
 10. A pump as in claim 9 wherein the contact ring is carried by an annular carrier of electrically insulating material, which carrier is brought back by a spring into a position in which the limit switch is closed, the action of which spring is compensated by the switching member before said switching member opens said switch.
 11. A pump as in claim 9 in which the contact ring is carried by the second co-axial sleeve made of electrically insulating material, said second sleeve being axially movable in the pump housing with such a play, that it can be moved by the switching member into a position in which the limit switch is open, and is moved back to its starting position in which said switch is closed in response to the movement of the pumping member when the pumping member approaches the end of its return stroke.
 12. A pump as in claim 11 in which the contact ring is locked against rotation with respect to the second co-axial sleeve by means of V-shaped axial grooves arranged in the periphery of said contact ring, which grooves are provided each at their bottom with a recess into which the contacts of the limit switch are snapped in the closed position of said limit switch, the carrier of the contact ring being provided with similar grooves in line with the grooves of the contact ring.
 13. A pump as in claim 1 iN which the pitch of the screw-thread joining the first co-axial sleeve to the cylindrical portion of the rod-like member of the pumping member is at least equal to the maximum stroke length of the pumping member. 